Multi-Propulsion, Multi-Fuel Marine Power System

ABSTRACT

A marine propulsion and power supply for maritime vessels that includes an arrangement of modules that can be internal combustion engines, regenerative electric motors, engine generators, turbine generators and/or battery banks. These components can be arranged in such a way as to work together to increase efficiency and to utilize various fuel combinations to achieve the lowest overall operating cost or other goals whilst minimizing harmful emissions. Sensors can be used monitor various power parameters and can be coupled to a closed-loop in a control system to achieve vessel operating goals.

This application is related to, and claims priority from, U.S. Provisional patent application No. 61/657,965 filed Jun. 11, 2012. Application 61/657,965 is hereby incorporated by reference in its entirety.

BACKGROUND

1. Field of the Invention

The present invention relates to marine propulsion systems and more particularly to a multi-propulsion, multi-fuel marine power system.

2. Description of the Prior Art

Typical marine propulsion systems usually have a main engine or a pair of main engines. Many times these main engines are diesel. The main engine or engines also often drive a generator that is used for battery charging. The battery is used primarily for starting the engines.

A major problem with prior art systems is that they can only run on one fuel. Usually this is diesel fuel for larger vessels. In some cases, smaller vessels may instead have gasoline engines; however, these are usually recreational vessels.

It would be very advantageous to have a marine propulsion system that could contain a mix of different power systems that could run on different fuels to take advantage of fuel pricing. It would also be advantageous to use generators to store electrical energy in batteries that could then be used to drive electric motors. Combination generator/motor units would also be advantageous.

It would also be advantageous to have sensors that monitor various power parameters and that could be fed back into a control system.

SUMMARY OF THE INVENTION

The present invention relates to a marine propulsion and power supply for maritime vessels that includes an arrangement of modules that can be internal combustion engines, regenerative electric motors, engine generators, turbine generators and/or battery banks. These components can be arranged in such a way as to work together to increase efficiency and to utilize various fuel combinations to achieve the lowest overall operating cost or other goals whilst minimizing harmful emissions. Sensors can be used to monitor various power parameters and can be coupled to a closed-loop in a control system to achieve vessel operating goals.

DESCRIPTION OF THE FIGURES

Attention is now directed to several drawings that illustrate features of the present invention.

FIG. 1 shows a schematic of a propulsion system.

FIG. 2 shows different types of fuel that can power embodiments of the present invention.

FIG. 3 shows a control system used with embodiments of the present invention.

Several drawings and illustrations have been presented to aid in understanding the present invention. The scope of the present invention is not limited to what is shown in the figures.

DESCRIPTION OF THE INVENTION

The present invention includes a collection of modules that may be internal combustion engines, regenerative electric motors, engine generators, turbine generators and battery banks.

The components can be switched in and out to work together to achieve a lowest overall operating cost and/or minimizing harmful emissions.

A minimum system contains at least one main engine. In a preferred embodiment, the main engine is a tandem combination of an internal combustion sub-engine and an electric machine sub-engine. A typical twin propeller application can utilize two main engines. These are normally configured with the same equipment; however, it is within the scope of the present invention to configure the two main engines differently in a twin propeller application. A single main engine can also drive two or more propellers.

The main engine(s) is normally mechanically coupled to the propeller shaft(s). The system can include a generator module or modules, either as a part of the main engine or separate, which are not directly connected to the drive-line, but which can boost or provide power to the main engine as well as provide general house power for the vessel. The generating modules can be made up of an alternator or generator and can be driven by a turbine and/or additional sub-engine. The generating modules and internal combustion sub-engines are able to run on various fuels which include liquid and gaseous hydrocarbon fuels such as standard marine diesel fuel, gasoline, bio-fuel oil or natural gas. As such, the system allows for the flexibility to utilize multiple fuels simultaneously or independently.

Each main engine can include a tandem arrangement of an internal combustion sub-engine and an electric sub-engine. These sub-engines can be connected through a combining drive transmission which allows them to work together to provide the rotational force necessary to drive the propeller at full capacity. In addition, the combining transmission can be uncoupled from the internal combustion sub-engine to allow for various drive combinations where the electric sub-engine can exclusively supply the power to turn the propeller. Alternatively, leaving a sub-engine coupled through the combining transmission while not supplying power from the generating module to the electric sub-engine can cause the electric sub-engine to be “dragged” or over hauled which then allows the electric sub-engine to regenerate (become a generator). The regenerated power is then available for other house or propulsive needs.

When the system includes a pair of main engines, there are many possibilities for different configurations where power can be split and shifted between all the various elements. The selection and balancing of these elements can be done manually, but can be optimized by a logic control system that takes into account efficiencies of the various sub-systems, feedback relating to torque loading, shaft speeds, engine RPMs, fuel flow, combustion monitoring, temperature, barometric pressure and fuel costs and selection to provide the lowest operating cost, the lowest emissions, or the lowest fuel usage.

FIG. 1 shows an embodiment of the present invention with two main engines and two propeller shafts (and propellers). Both main engines 1, 2 include an internal combustion engine 3 in tandem with an electric motor 4. The electric motor 4 can act as a generator if “dragged” as described above. Each tandem engine can be connected through a transmission or gear reduction 5 to transfer proper torque and screw RPM, or in some cases, the electric motor can be connected without a clutch (it can still free-wheel if desired). Both the internal combustion engine 3 and the electric motor 4 can be connected to the transmission 5 with clutches 6.

FIG. 1 also shows a battery bank 7, a turbine engine 8, and an engine generator 9. Both the turbine generator 8 and the engine generator 9 can supply electric power to charge the battery bank 7 and to run the electric motors 4. In addition, if one or both of the electric motors 4 are being “dragged” (in regeneration mode), power from these motors 4 can be used to charge the battery bank 7.

FIG. 2 shows that different types of fuel can be used to power the internal combustion engines 3 and the generating modules 9. In particular, the engines 3 can be configured to run from diesel fuel 10, compressed or liquid natural gas 11, gasoline 12, and any other type of fuel. Different embodiments of the present invention may have different combinations or choices of these and other fuels. Any fuel combination is within the scope of the present invention. Also, the engine generator 9 can be configured to run on different fuels in a manner similar to the main engines.

The system of the present invention creates numerous possibilities and combinations to achieve maximum efficiency and lowest cost. Some examples are 1) The internal combustion engines 3 power the propellers, while the motors 4 charge the batteries 7. 2) Both the internal combustion engines 3 and the motors 4 power the propellers, while the turbine generator 8 and/or engine generator 9 charges the batteries 7. 3) The electric motors 4 power the propellers, while the electric generator 9 charges the batteries 7. 5) The electric motors 4 power the propellers with no battery charging. 6) The turbine 8 alone can drive the propellers. In addition, the captain or the control system may choose to run on only one main engine which alone can be configured to turn both propellers. A mode where only one propeller is turned on a two-propeller vessel is not usually used in service when there are twin propellers since it creates a turning force that has to be counteracted by the rudder increasing drag through the water. Also, the non-turning propeller itself creates additional drag. Nevertheless, this mode might be used in an emergency situation where there was a failure of one of the main engine systems. The control system can attempt to optimize service in this special mode. Of course, if the vessel only has one main engine, this is not a consideration. These examples have been presented only to show a few of the possibilities. The scope of the present invention is not limited to what is described in any of the examples.

FIG. 3 shows a automatic feedback control system 12. This can be located in a computer or PLC or any other type of computing device. It can also be mechanical or electrical. The computer or PLC typically includes a processor and memories that contain stored data and executable programs. The programs can include expert systems, fuzzy logic, optimization and any other programs or algorithms.

The control system 12 is coupled to several sensors 13 that provide input information such as engine RPMs, shaft RPM, torques, fuel use rate, fuel quantities, battery charge state, battery charge rate, other voltages and/or currents. A GPS receiver 14 can provide absolute vessel speed and heading as well as vessel location. Weather sensors can provide wind velocity and direction, wave height, and other external parameters. Fuel prices by type can be periodically input into the control system 12 or can by dynamically updated via a radio or internet link 15. Fuel prices may vary with location, so the vessel location along with stored or updated fuel prices can be used to compute maximum efficiency. The type of load the vessel is carrying (or pushing or towing) (or the effects of that load) can be entered manually, or calculated based on speeds, torques and RPMs. This can be factored into the control system algorithms.

The control system can attempt to achieve various goals that can be chosen by the captain or crew members such as 1) lowest cost, 2) fastest trip, 3) minimum emissions, 4) lowest fuel usage, or 5) an attempt to optimize all of these goals. Any efficiency goals are within the scope of the present invention.

Several descriptions and illustrations have been presented to aid in understanding the present invention. One with skill in the art will realize that numerous changes and variations can be made without departing from the spirit of the invention. Each of these changes and variations is within the scope of the present invention. 

I claim:
 1. A high efficiency propulsion system for a marine vessel comprising: a plurality of rotating power sources of different types coupled to at least one propeller; wherein, at least one of these power sources is a regenerative electric motor and at least one is an internal combustion engine; a battery electrically connectable to said at least one regenerative electric motor; a turbine powered generator electrically connectable to propulsion systems; an engine generator electrically connectable to said battery; a control system programmed to select combinations of power sources from said plurality of rotating power sources; whereby, said control system optimizes vessel performance based on a predetermined efficiency goal.
 2. The high efficiency propulsion system of claim 1 wherein said control system further controls one of said turbine powered generator or said engine generator.
 3. The high efficiency propulsion system of claim 1 wherein said control system contains a processor.
 4. The high efficiency propulsion system of claim 1 wherein said predetermined efficiency goal is selected from the group consisting of lowest cost, fastest trip, minimum emissions and lowest fuel usage.
 5. The high efficiency propulsion system of claim 1 further comprising a plurality of sensors coupled to said control system.
 6. The high efficiency propulsion system of claim 5 wherein said sensors are selected from the group consisting of engine RPM, shaft RPM, torque, fuel use rate, fuel quantity, battery charge state and battery charge rate.
 7. The high efficiency propulsion system of claim 1 further comprising a GPS receiver coupled to said control system that can provide absolute vessel speed and heading as well as vessel location.
 8. The high efficiency propulsion system of claim 1 further comprising weather sensors coupled to said control system that can provide wind velocity and direction and wave height.
 9. The high efficiency propulsion system of claim 1 wherein said control system receives dynamically updated fuel prices. 